A storage system typically comprises one or more storage devices into which information may be entered, and from which information may be obtained, as desired. The storage system includes a storage operating system that functionally organizes the system by, inter alia, invoking storage operations in support of a storage service implemented by the system. The storage system may be implemented in accordance with a variety of storage architectures including, but not limited to, a network-attached storage environment, a storage area network and a disk assembly directly attached to a client or host computer. The storage devices are typically disk drives organized as a disk array, wherein the term “disk” commonly describes a self-contained rotating magnetic media storage device. The term disk in this context is synonymous with hard disk drive (HDD) or direct access storage device (DASD).
The storage operating system of the storage system may implement a high-level module, such as a file system, to logically organize the information stored on volumes as a hierarchical structure of data containers, such as files and logical units. For example, each “on-disk” file may be implemented as set of data structures, i.e., disk blocks, configured to store information, such as the actual data for the file. These data blocks are organized within a volume block number (vbn) space that is maintained by the file system. The file system may also assign each data block in the file a corresponding “file offset” or file block number (fbn). The file system typically assigns sequences of fbns on a per-file basis, whereas vbns are assigned over a larger volume address space. The file system organizes the data blocks within the vbn space as a “logical volume”; each logical volume may be, although is not necessarily, associated with its own file system.
A known type of file system is a write-anywhere file system that does not over-write data on disks. If a data block is retrieved (read) from disk into a memory of the storage system and “dirtied” (i.e., updated or modified) with new data, the data block is thereafter stored (written) to a new location on disk to optimize write performance. A write-anywhere file system may initially assume an optimal layout such that the data is substantially contiguously arranged on disks. The optimal disk layout results in efficient access operations, particularly for sequential read operations, directed to the disks. An example of a write-anywhere file system that is configured to operate on a storage system is the Write Anywhere File Layout (WAFL®) file system available from Network Appliance, Inc., Sunnyvale, Calif.
The storage system may be further configured to operate according to a client/server model of information delivery to thereby allow many clients to access data containers stored on the system. In this model, the client may comprise an application, such as a database application, executing on a computer that “connects” to the storage system over a computer network, such as a point-to-point link, shared local area network (LAN), wide area network (WAN), or virtual private network (VPN) implemented over a public network such as the Internet. Each client may request the services of the storage system by issuing file-based and block-based protocol messages (in the form of packets) to the system over the network.
A plurality of storage systems may be interconnected to provide a storage system cluster configured to service many clients. Each storage system may be configured to service one or more volumes, wherein each volume stores one or more data containers. In certain storage system clusters, data container content may be striped across a plurality of volumes configured as a striped volume set (SVS), where each volume is serviced by a different storage system, thereby distributing the load for the single data container among a plurality of storage systems. A cluster environment for data container striping is described in U.S. Pat. No. 7,698,289, issued on Apr. 13, 2010, entitled STORAGE SYSTEM ARCHITECTURE FOR STRIPING DATA CONTAINER CONTENT ACROSS VOLUMES OF A CLUSTER, by Richard Jernigan, et al.
Many of the administrative tasks that are performed in order to manage a storage system cluster involve complex and/or potentially long running operations. Certain tasks (jobs) may be required to run on a particular storage system within the cluster, while others may run on any storage system within the cluster. A job may comprise of a plurality of processes and/or threads operating in an organized fashion to complete the task. A noted disadvantage in conventional clustered storage systems is that an administrative command that initiates a job may need to be executed on the particular storage system on which the job is to be performed. This complicates cluster management by requiring a storage system cluster administrator to log into each of the storage systems to perform certain jobs.
A noted requirement for proper management, however, is that once a job has begun, the job must run to completion even in the event of a storage system failure. Additionally, if the job cannot run to completion, then the job must make a “clean” exit by, for example, deleting any temporary files created. In typical storage system clusters, these requirements have necessitated manual intervention on behalf of system administrators, thereby reducing system robustness for mission-critical clustered environments. For example, should a job be initiated on a particular storage system, which then suffered a failure prior to the completion of the job, an administrator would need to identify that the job did not complete and manually re-initialize the job on another storage system.